Air compressor



M. B. MORGAN AIR COMPRESSOR Nov. 4, 1930.

Filed Aug. 24, 1929 23 5 F'Z Z2 6 M 4 6 m 0 m a a 6 w W W 0 L w 7 W 6, aM W w 1 RN /w. a 9 6 Mr Z 6 J Patented Nov. 4, 1930 UNITED STATES PATENTOFFICE MATHEW IB, MORGAN, OF DETROIT, MICHIGAN, ASSIGNOB TO THETIMBER-DETROIT AXLE COMPANY, OF DETROIT, MICHIGAN, A CORPORATION "OFOHIO AIR COMPRESSOR Application filed August 24,

This invention relates to fluid pumps and is particularly applicable toair compressors. Its principal objects are to devise an air compressorthat will be economical to produce, maintain and operate, that will bequiet and positive in action, that will be compact, strong, durable andof large capactaken on the line 11 in Fig. 2,

Fig. 2 is a transverse cross-section on the line 2-2 in Fig. 1,

Fig. 3 isan end elevation with parts shown in transverse section,

Fig. 4. is a longitudinal sectional view of the cam member; and

Fig. 5 is adiagram illustrating a complete cycle of operation for eachrevolution of the piston around the axis of the shaft.

The present device comprises a short cylindrical or annular member 1,hereinafter called a cam member, with a cylindrical inner surface onwhich is a continuous rib 2 which is arranged obliquely with referenceto the'longitudinal axis of said surface, and constitutes a cam. Thesides of said rib are beveled. Each of a number of cylindrical pistonsor piston members 3 (four in the construction shown) is provided midwayof its length with a circumferential groove 4 with beveled sides and ofproper width to roll freely over the cam rib 2. Each end of each pistonfits in a cylindrical chamber 5, hereinafter called a piston chamber,formed in the marginal portion of a rotor 6 composed of two. alinedcounterpart members. 7 of cylindrical form. Each of said cylin- 1929.Serial no. 388,048.

drical members has as many piston chambers as the number of pistons,such chambers being disposed longitudinally in said member andequi-distant from each other.

The inner ends of said cylindrical member 7 abut against each otherexcept at their peripheral portions, where they are recessedsufiiciently to receive the cam member 2 freely between them. The outerends of said cylindrical members are closed by end caps or closureplates 8 that are clamped firmly together by long threaded bolts 9 thatextend through said cylindrical members and are tightened b nuts 10therein. Said cylindrical mem ers are accurately centered by dowels orpins 11 in their meeting faces, with their piston chambers in alinement;and the outer ends of said cylindrical members have axial openings whichfit over centering lugs 12 provided therefor in the inner faces of theclosure lates. Each closure plate has a stub sha 13 formed integraltherewith.

The two stub shafts 13 are journaled in bushings or antifrictionbearings 14 mounted in hubs 15 provided therefor in the ends of astationary casing 16. The casing is made of two hollow cylindricalmembers '17 closed at their outer ends and open at their inner ends. Thecasing members fit over the rotor 6, with their inner ends bearing overand against the cam member 1 whose ends are recessed to receive saidcasing members. Said casing members 17 are secured together by longbolts 18 that extend endwise through them and the intervening cam member1 and are provided with nuts 19 on their threaded ends. The closed endsof said casing members are formed into the hubs 15 adapted to receivethe bearings 14 for the stub shafts 13 that are inte rotor. ne of saidstub shafts is suitably connected to a source of power to be driventhereby.

It is apparent from the foregoing description that when power is appliedto the rotor, said rotor is rotated on its axis carrying the severalpistons with it. As the pistons continuously engage the cam rib 2, whichis 'stationary, the revolution of the pistons about 100 al with theclosure plates of the the axis of the shaft causes such pistons to moveendwise in their chambers an amount equal to the throw of the cam rib;and it is this reciprocating movement of the piston that is utilized forpumping or compressing.

All of the pistons operate alike; and the timing of one of them isillustrated by the diagram shown in Fig. 5 wherein there is acompletecycle of operation for each revolution of the piston around theaxis of the shaft.

ed at the opposite end of the same piston, but

the phase of the cycle at one end of the piston-is 180 different fromthe phase at the other end of said piston In order to rovide for suchoperation, a radial port 21 1s formed in the side wall of each p stonchamber in position to register with a circumferentially elongatedgroove 22 (about 135 in the example) in the inner cylindrical surface ofthe casing, which groove communicates through a passageway 23 in thecasing to the source of fluid supply. The portion of the piston oppositesaid port is of reduced diameter, such reduced portion 24 being of suchwidth that said port is always opposite some portion thereof. Crossbores 25 are formed in the piston in the portion of reduced diameter andcommunicate with an'axial bore 26 that extends to the end thereof. Bythis arrangement, the groove 22, which is in communication with thesource of fluid supply remains in communication with the admission portof each, piston chamber throughout 135 of its revolution, and duringthis period the fluid asses from the groove to the radial port 0 thepiston chamber and thence through the annular space surrounding thereduced portion of the piston into the cross ports of the piston andthence through the longitudinal bore in the piston into the end of theiston chamber. As soon as the radial port of t e piston chamber passesthe end of the groove in the casing, communication with the source offluid supply is cut off, the fluid charge is trapped in the pistonchamber, and the operation of compression thereof begins and continuesuntil the opening of the exhaust port? The exhaust passageway 27 extendslongitudinally of the wall of the casing and opens into acircumferentially elongated groove 28 in the inner wall thereof. In theexample, this exhaust groove'extends through an angle of about'20.Opposite this exhaust groove is the port or passageway 21 that extendsthrough the wall of the piston chamber opposite the reduced portion ofthe piston. By

tions of the two cylinderical members 0 the rotor, Where the lubricantis in direct contact with the cam rib,2 and the exposed middle portionsof the piston members, including the cam engaging grooves therein. Asthe cam rib remains stationary while the piston working in engagementtherewith revolves around the axis of the shaft, there is enoughfriction between them to cause rotation of the piston members on theirrespective axes, Advantage is taken of this fact to overcome thevtendency of the lubricant to get into the charge of fluid. For thispurpose, the cylindrical surfaces of each piston member adjacent to themain groove 4 thereof which cooperates with the cam rib are providedwith small helical grooves that start at the wall of said main grooveand preferably make several turns around the piston member. The two oilgrooves are of opposite hand to each other and their lead is such that,as the piston member rotates on its axis in its normal direction, thepoints of intersection of the two oil grooves with any givenlongitudinal plane continuously approach each other. Thus theirinclination or direction is such that they tend to fling the oil towardthe main groove and thus tend to keep the oil or lubricant from creepinginto the chamber beyond the end of the piston.

While the device hereinbefore described is especially adapted to be runat high speed for compressing air, it is adapted for use with othercompressible fluids; and by properly correlating the intakeand dischargepassageways in accordance with common practice, said device may be foundused for pumping liquids.

For the purpose of regulating the compressor, provision is made forshifting the cam mem er 1 circumferentially with relation to the othercasing members. For this purpose, it is only necessary to loosen andremove the clamping bolts, turn the cam member to bring new holestherein into register with the holes in the casing members, pass thebolts through them and tighten the nuts thereon. Of course, the holesthrough the cam member are arranged in groups of the same number as thebolts and distributed so that all of the members of each group willsimultaneously register with the bolt holes in the cas- It is noted thatthe device is very compact, that its parts are easy and simple tomanufacture and assemble, that the device is well balanced and welladapted to run at high speed, that all of its parts are simple, strongand durable; that its lubrication system is simple and efiicient andprotects the fluid charge against contamination with lubricant, that thedischarge is subject to considerable range of adjustment, and that thereis little likelihood of any of the parts getting out of order.

What I claim is:

1. A pump comprisinga casing having fluid distributing passagewaystherein and having a continuous cam rib on the interior thereof, acylindrical rotor rotatable in said casing and having a plurality ofpiston chambers arranged therein in alined pairs, and a reciprocatablepiston member for each pair of chambers, each piston member having acircumferential groove at the middle thereof adapted to receive said camrib and each piston member having a portion of reduced diameter in eachend portion thereof and a passageway from said. reduced portion throughthe end of said piston member, and the rotor having passageways openinginto the respective piston chambers opposite the reduced portions of thepiston members and arranged to communicate periodically with saidfirst-mentioned passageways, respectively. 4

2. An air compressor comprising a casing having fluid distributingpassageways theren and having a continuous. cam rib on the interiorthereof, a cylindrical member rotatable in said casing and having aplurality of piston chambers therein, a reciprocatable piston in eachchamber having a circumferential groove near the middle thereof adaptedto receive said cam rib and passageways communicating with saidfirst-mentioned passageways, respectively, opening into the respecnvepiston chambers, each piston havmg a distributing groove encircling itand a passageway from said groove through the end thereof.

3. A pump comprising a casing having fluid distributing passagewaystherein and having a continuous cam rib on the interior thereof, and 'acylindrical rotor rotatable in said casing and having a plurality ofpiston chambers therein, and a reciprocatable piston in each chamberhaving a circumferential groove near the middle thereof engaging saidcam rib, said rotor having passageways arranged to communicateperiodically with said first-mentioned passageways respectively andopening into the respective piston chambers, each piston having aportion of reduced diameter opposite the adjacent rotor passageway andalso having a passageway from such reduced portion through the adja centendof said piston.

4. A pump comprising a casing havin a continuous cam rib on the interiorthereo a cylindrical rotor rotatable in said casing and having aplurality of piston chambers therein, and a reciprocatable piston ineach chamber having a circumferential groove near'the middle thereofengaging said cam rib, said casing and said rotor and said piston beingprovided with appropriate passageways for pumping, said casingcomprising an annular member on the inner face of which is said cam riband two cylindrical members abutting against said cam member and havingjournal bearings on their outer ends for said rotor, and said rotorcomprising counterpart cylindrical members adapted to fit in said casingwith their inner ends abutting against each other and with theperipheral portions of said inner ends recessed to freely accommodatesaid cam member, said rotor also comprising end closure plates that areprovid ed with shafts that are journalcd in said bearings, andlongitudinal clamping bolts clamping said end plates together.

5. A pump comprising a casing having a continuous cam rib on theinterior thereof, a cylindrical rotor rotatable in said casing andhaving a plurality of piston chambers therein, and a reciprocatablepiston in each chamber having a circumferential groove near the middlethereof engaging said cam .rib, said casing and said rotor and saidpiston being provided with appropriate passageways for pumping, saidcasing comprising an annular member on the inner face of which is saidcam rib and two cylindrical members abutting against said cam member andhaving journal bearings ontheir outer 'ends for said rotor,-said cammember and said end members having longitudinal symmetrically arrangedholes and fastening bolts extending through said holes whereby saidparts may be adjusted circumferentially with relation to each other, andsaid rotor comprising counterpart cylindrical members ada ted to fit insaid casing with their inner ends a utting against each other and withthe peripheral portions of said inner ends recessed to freelyaccommodate said cam member, said rotor also comprising closure platesthat are provided with shafts that are journaled in said bearings.

6. Aipump comprising a casing having a continuous cam rib on theinterior thereof, a cylindrical rotor rotatable in said casing andhaving a plurality of piston chambers therein, and a reciprocatablepiston in each chamber having a circumferential groove near the middlethereof engaging said cam rib, said casing and said rotor and saidpiston being provided with appropriate passageways for pumping, saidcasing comprising an annular member on the inner face of which is saidting against said cam member and having journal bearings on their outerends for said rotor and means for securing said members together withsaid annular member in either of a plurality of different positions ofrotary adjustment.

7. A pump comprising a casing havin a continuous cam rib on the interiorthereo a cylindrical rotor rotatable in said casing and having aplurality of iston chambers therein, and a reciprocatab e piston in eachchamber having a circumferential groove near the middle thereof engagingsaid cam rib, said casing and said rotor and said piston being providedwith appropriate passageways for pumping, said casing comprlsing anannular member on the inner face of which is said cam member and twocylindrical members abutting against said cam member and having journalhearings on their outer ends for said rotor, said cam member and saidend members having longitudinal holes, and fastening bolts extendingthrough said holes.

8. A pump comprising a casing having a continuous cam rib on theinterior thereof, a cylindrical rotor rotatable in said casing andhaving a plurality of pistonch'ambers therein, and a reciprocatablepiston in each chamber having a circumferential roove near the middlethereof engaging sai cam rib, said casing and said rotor and said'pistonbeing provided with appropriate passageways for pum ing, said casingcomprising an annular mem er on the inner face of which is said cam riband two cylindrical members abutting against said cammember and havingjournal bearings on their outer ends for said rotor, said cam member andsaid and members havmg longitudinal s mmetrically arranged holes, andfastening olts extending through said holes whereby said parts may beadjusted circumferentially with relation to each other.

9. A pump comprising a casing having a continuous cam rib on theinterior thereof, a cylindrical rotor rotatable in said casing andhaving a plurality of iston chambers therein, and a reciprocatab episton in each chamber having a circumferential groove near the middlethereof engaging said cam rib, said casing and said rotor and saidpiston being provided with appropriate passageways for pum ing, saidcasing comprising an annular mem r, on the inner face of which is saidcam rib, and two cylindrical members abutting against said cam memberand having journal bearings on their outer ends for said rotor, said cammember and said end mem: bers having longitudinal symmetrically arrangedholes, and fastening bolts extending through said holes whereby saidparts may be adjusted circumferentially with relation to each other, andsaid rotor comprising count-erpart cylindrical members adapted to fit insaid casing with their inner ends abutting against each other and withthe peripheral portions of said inner ends recessed to freelyaccommodate said cam merhber, said rotor also comprising closure platesthat are provided with shafts that are journaled in said bearings, andlongitudinal clamping bolts clamping said end plates together.

10. A pump comprising a casing having a continuous cam rib on theinterior thereof, a cylindrical rotor rotatable in said casing andhaving a plurality of piston chambers therein, and a reciprocatablepiston in each chamber having a circumferential groove near the middlethereof engaging said cam rib, said casing and said rotor and saidpiston being provided with appropriate passageways for pumping, saidcasing comprising an annular mem er on the inner face of which is saidcam rib and two cylindrical members abutting against said cam member andhaving journal bearings on their outer ends for said rotor, said cammember and said end members having longitudinal symmetrically arrangedholes, and fastening bolts extending through said holes whereby saidparts may be adjusted circumferentially with relation to each other, andsaid rotor com rising counterpart cylindrical members a apted to fit insaid casing with their inner ends abutting against each other and withthe pe- -ripheral portions of said inner ends recessedto freelyaccommodate said cam member, said rotor also comprising closure platesthat are provided with shafts that are journaled in said bearings, andlongitudinal clamping bolts clamping said end plates together.

11. A pump of the kind described comprising a casing which comprises anannular cam member having a continuous cam rib on the interior thereofand two alined cylindrical members on opposite sides of said cam member,a cylindrical rotor rotating in said casing and comprising counterpartcylindrical members adapted to fit in said casing with their inner endsabutting against each other and with the peripheral portions of saidinner ends recessed to accommodate the cam rib portion, each of saidrotor members having a plurality of piston chambers therein alined withthe piston chambers of the other rotor members, reciprocatable pistonmembers each having a circumferential groove in the middle thereofengaging said cam rib and with its end portions working in alined pistonchambers.

12. A pump of the kind described comprise ing a casing comprising anannular cam member having a continuous cam rib on the interior thereofand two alined cylindrical mem? bers on opposite sides of said cammember, a cylindrical rotor rotating in said casing and comprisingalined cylindrical members adapted to fit in said casing with theirinner ends abutting against each other and with the peripheral portionsof said inner ends recessed to accommodate said cam member, each of saidrotor members having a plurality of piston chambers therein alined withthe piston chambers of the other rotor members, reciprocatable pistonmembers each having a circumferential groove in the middle thereofengaging said cam rib and with its end portions working in alined pistonchambers, said casing having a passageway for lubricant opening into thespace adjacent to said cam rib, and said piston member having helicalgrooves of opposite hand extending from the main groove thereof, thehand of each helical groove being such that its point of intersectionwith any longitudinal plane approaches the main groove as the pistonrotates in normal direction.

13. A pump of the kind described comprising a casing having a continuouscam rib on the interior thereof, a cylindrical rotor rotating in saidcasing and comprising counterpart cylindrical members adapted to fit insaid casing with their inner ends abutting against each other and withthe peripheral portions of said inner ends recessed to accommodate thecam rib portion, each of said rotor members having a plurality of pistonchambers therein alined with the piston chambers of the other rotormembers, reciprocatable piston members each having a circumferentialgroove in the middle thereof engaging said cam rib and with its endportions working in alined piston chambers, said casing having apassageway for lubricant o ening into the space adjacent to said-cam ri,and said piston member having helical grooves of opposite handextending from the main groove thereof, the hand of each helical groovebeing such that its point of intersection with any longitudinal planeapproaches the main groove as the piston rotates in normal direction.

Signed at Detroit, Michigan, this 19th day of August, 1929.

MATHEW B. MORGAN.

